I have to put a new rear tyre on my new to me Husky. The manual states 140/80 18. Currently there is a Dunlop D 606 in 130/90 18 fitted. @chopperpilot included a new D606 in the sale but this one is 120/90 18. I would like to stick with the 606.

I understand the differences in sizes but don't know how the different sizes will affect the handling, grip and other things.

What are you running on your bikes and do you venture away from the recommended sizes?